With reference to the above video;
I have long held the opinion that the "mark one eyeballs" is seriously limited (in airborne humans) thus making the "see and avoid" mantra, promoted by so many pilots/instructors, at best misleading, at worst a danger in itself.
My opinion, in this matter, is often hotly refuted.
I contend, that good radio communication, procedural adherence/discipline, are likly the greater safety skills, that "clue" the pilot into the location of the other airborne aircraft(s) and thus visual acquisition (not the other way around).
In the above video - dodgy radio (lack of communication), structural visual blocking, questionable procedures and the limitations of the human eye, combined to create a disaster.
The helicopter tragedy supports my argument all too well.π